Although it is clear that NO mediated activation of sGC is the most profound mechanism of regulation, regulation of "basal" or NO-independent sGC activity may be of equal physiological importance. It is the intent of this proposal to investigate other factors regulating sGC such as cellular redox status or metal homeostasis. Our aims are to determine the role of thiol redox chemistry and thlol modification on the activity and regulation of sGC, investigate the role of sGC activation by CO arid NO upon thiol modification and thiol redox chemistry arid to determine the metal binding properties of sGC and the effects of metal binding on activity/regulation. To accomplish our aims we will ascertained the redox status of the cell by measuring both the levels of GSH and the GSH/GSSG ratio. Identical experiments run in parallel will be performed except that cGMP will be measured. The ability of cellular sGC to be activated by NO and CO as a function of cellular redox status will be determined by performing experiments similar to those described above except that NO and CO will be added to the incubations to activate the enzyme. Similarly sGC activity will be determined upon exposed to a variety of metals (e.g. Cu, Zn, Pb, Cd, Ag, As, Hg). [unreadable] [unreadable]